The producing method of an objective compound by using a biocatalyst is used for producing many compounds, because it has some advantages, for example, reaction conditions are mild, a product having a high purity can be obtained since an amount of by-product is small, and a production process can be simplified. For example, in the case of production of an amide compound such as acrylamide, since nitrile hydratase, which is an enzyme for converting a nitrile compound such as acrylonitrile into an amide compound, was found, biocatalysts including the enzyme have been widely used.
In the case of producing acrylamide using the biocatalyst, it is necessary to remove a reaction heat. In general, the biocatalyst is easily deactivated with heat. A reaction which converts the acrylonitrile to acrylamide is an exothermic reaction, and a temperature of a reaction solution rises by the reaction heat. If the reaction heat is not sufficiently removed, the biocatalyst is deactivated by the heat.
The method for removing the reaction heat, for example, a method of cooling with a heat exchanger by circulating a portion of a reaction mixture to a pump circulation passage, using a reactor comprising the pump circulation passage which provided with the heat exchanger (Patent Document 1), a method of using a plug flow type reactor which is a double pipe type or a shell and tube type (Patent Document 2), and a method which is providing a jacket or cooling coil to a reaction tank (Patent Document 3), has been known.